Electrically conductive cable

ABSTRACT

Improvements are taught in the preparation of olefin coated electrically conductive cables wherein the space between individual singles wires within the cable is filled with petroleum jelly. The improvement comprises stabilizing the polymer coating on the singles wires with a specified thiobisphenol phosphite which is particularly resistant to extraction by petroleum jelly.

United States Patent 91 McTigue ELECTRICALLY CONDUCTIVE CABLE [75]Inventor: Frank H. McTlgue, Wilmington, Del.

[73] Assignee: Hercules Incorporated, Wilmington,

Del.

[22] Filed: Sept. 15, 1971 [2]] Appl. No.: 180,842

[52] US. Cl 174/23 C, 117/232, 174/1 l3, 174/116 [51] Int. Cl H02315/20, B44d 1/42 [58] Field of Search 174/23 C, 113, 116; 117/232 [56]References Cited UNITED STATES PATENTS 3,668,298 6/1972 Hawkins l74/23Aug. 28, 1973 3,354,117 ll/l967 Schmidt et al 260/45.85

Primary Examiner-William D. Martin Assistant Examiner-Harry l. GwinnellA tr0rney-William S. Alexander and Edwin H. Dafter, Jr.

I 5 7] ABSTRACT 4 Claims, No Drawings ELECTRICALLY CONDUCTIVE CABLE Thisinvention relates to a new and improved electrical conductor suitablefor use in underground installations. More specifically it relates toelectrical or communications cables comprised of a plurality ofindividual polyolefin coated wires.

An electrical or communications cable is comprised of a great number ofpairs of single conductive wires. Each of these singles is coated with adielectric material to insulate them all individually from one another.A large number of these singles are then collected into a bundle whichis the cable. The cable is coated on'the outside with a sheath of adielectric material to make an integral structure.

As is to be expected, collecting a plurality of round wires into a cableresults in a large volume of unoccupied space between wires. In thenormal course of things this is simply dead space which becomes filledwith air. In many applications this is satisfactory since air is anexcellent dielectric. However, when the cable is intended to beinstalled underground, this type cable is usually not satisfactory. Thereason for this is that an underground cable is frequently in contactwith water. If a flaw develops in the outer sheath, water can leak intothe dead space in the cable and this can eventually lead to trouble suchas, e.g., shorting of apair of wires.

In order to keep water out of these cables in underground installations,it has become common practice to fill the cable with an inexpensiveliquid or low-melting solid dielectric. The most preferred materialfound for this application is petrolatum or petroleum jelly i.e., a lowmolecular weight, amorphous, semi-solid hydrocarbon mixture melting atabout 34 to 60C. The filling composition actually used in the cable iscomposed of 80 to 95 percent petrolatum and 5 to percent low or mediumdensity polyethylene. The filling compounds become fluid at 100 to 125C.

Unfortunately, the use of petroleum jelly is not a satisfactory solutionto the problem, when the dielectric coating on the individual wirestrands or the sheath is a polyolefin such as polyethylene orpolypropylene. These materials contain heat stabilizers and copperinhibitors which are readily extracted therefrom by the petroleum jellywhich is chemically very similar to the polymer in its structure. Heatstabilizers and copper inhibitors are needed in polyolefins for use infilled cable to protect the polymer, not only in the buried portion ofthe cable, but especially in the pedestals where the cables are broughtabove ground to make connections. These pedestals get quite warm insummer.

It is the purpose of this invention to provide an improved polyolefinjacketed electrical conductor which is not subject to the same highdegree of stabilizer extraction as is experienced with prior art cables.Concisely stated, the invention is an electrically conductive cableconsisting essentially of a plurality of conducting wires, said wiresbeing individually coated with an olefin hydrocarbon polymer containing,as a stabilizer, a hindered thiobisphenol phosphite and having the spacebetween said wires filled with an amorphous, semisolid, low molecularweight petroleum hydrocarbon melting at about 34 to 60C. Although thethiobisphenol phosphites have been recognized as polyolefin stabilizers,see US. Pat. No. 3,354,1 17, their ability to resist extraction bypetrolatum has been hitherto unrecognized.

The jacketed electrical conductors according to this invention can haveas their electrically conductive member either aluminum or copperaccording to known prior art. The make-up of the conductive member apartfrom the coating thereof forms no part of the invention.

As stated, the electrical conductors are coated with a solid polyolefin,i.e., a homopolymer of a single olefin or a copolymer of two or moreolefins. Preferred polyolefins are those based on ethylene andpropylene, for example, polyethylene, polypropylene and copolymerscontaining a preponderance of either ethylene or propylene.

The thiobisphenol phosphites employed in the practice of this invention,which are readily prepared by the reaction of PC1 with a thiobishindered phenol, having the general formula:

(llHa (THu CH3-$-CH1 cur-04m,

Rn Rn 3 where R is methyl or t-butyl and n is from 0 to 2.

The preferred thiobisphenol for use in preparing the thiobisphenolphosphites of this invention is 4,4- thiobis-(6-t-butyl-m-cresol).Others which can be employed include e.g. 4,4'-thiobis-(6-t-butylphenol), 4,4- '-thiobis-(2,6-di-t-butyl-m-cresol),4,4-thiobis-(2,6-dit-butyl phenol) and 4,4'-thiobis-(2-methyl-6-t-butylphenol), 2,2-thiobis(6-t-butyl p-cresol), 3,3- thiobis(6-t-buty1p-cresol), 2,2'-thiobis(6-t-butyl phenol) and 3,3 -thiobis(6-t-butylphenol).

The thiobisphenol phosphite is employed in concentrations of about 0.05to 1.0 percent bmethane,

bis-(4-oxy-3-methyl-phenyl)-pentane,

bis-(2-oxy-phenyl)-cyc1ohexane,

4,4 '-thiobis-( 6-t-butyl-m-cresol Naphthols and bisnaphthols, forexample, -dinaphthol, bis-(2-oxy-naphthyl)-methane, bis-(2-oxy-3-nonyl-naphthy1)-methane, 1,1,3-tris-(2-methyl-5-tbutyl-4-hydroxypheny1)butane, terpene-substituted phenols andbisphenols, for example, 6-isobomyl-ocresol, 6-isobornyl-l,2,4-xylenol,2,6-di-isobornyl-pcresol, 6-isobornyl-3,4-dimethyl-phenol, 2,6-di--isobornyl-3,4-dimethyl-phenol, 6,6-methylene-bis-(2-isobornyl-4-methylphenol), 6,6-methylene-bis-(2,4- di-isobornyl-phenol),can also be used.

Particularly suitable thioether compounds are those of aliphaticalcohols containing four to 18 carbon atoms such, for example, asdi-octylsulphide, didodecyl-sulphide, di-octadecyl-sulphide andbis(2-0xynaphthyl)-sulphide and the corresponding polythioethers, forexample di-dodecyl-disulphide, di-octyltrisulphide,di-octadecyl-tetrasulphide, and bis(2- oxynaphthyl)-disulphide esters,preferably those of aliphatic alcohols containing four to 18 carbonatoms such, for example, as thio-di-acetic acid dodecyl ester,thio-di-propionic acid lauryl ester, di-thio-di-butyric acid, octadecylester, di-thio-divaleric acid butyl ester, trithio-didecane-carboxylicacid nonyl ester, tetrathiodibutyric acid octyl ester ands-t-butyLmercapto-acetic acid lauryl ester. Salts of the thiodialkanoicacid esters such as zinc, calcium or sodium salts can also be used.

3 Petrolatum compositions fall into generally two main classificationsthose having high oil content and those having low oil content. Theinvention is applicable to either type of petrolatum. Generally, thehigh oil 4 molecular weight hydrocarbons. The low oil petrolatum has amelting point of about 43 to 60C., Saybolt viscosity of about 90 to l15, and contains about 12 to 15 percent oil.

petrolatum has a melting point of about 45 to 55C,, The extractabilityof the various stabilizers is deter- Saybolt viscosity of about 65 to73, and contains about mined by compounding the stabilizer into thepolymer 25 to 35 percent oil or methyl ethyl ketone soluble low andcompression molding the polymer into 21 i0 mil molecular weighthydrocarbons. The low oil petrolafilm. A portion of this film 1% X 1inch is placed in 50 turn has a melting point of about 43 to 60C.,Saybolt ml. of petroleum jelly and treated for 18 hours at 85C.viscosity of about 90 to 115, and contains about l2 to (j y to p y ratioabout 175 t0 The mm i8 percent oil. then removed from the petroleumjelly and wiped sub- The extractability of the various stabilizers isdeterstantially clean. A qualitative measure can be obtained mined bycompounding the stabilizer into the polymer by means of a 180 DTAinduction time. A quantitative and compression molding th a polyolefinsucmethane, measure can be obtained by infrared or U.V. analysisbis-(4-oxy-3-methyl-phenyl)-pentane, 15 before and after the extraction.bis-(2-oxy-phenyl)-cyclohexan The induction time is determined on aPerkin-Elmer 4,4-thiobis-(fi-t-butyl-m-cresol). Differential ScanningCalorimeter by heating the film N h h l d bi h h l f example, di hon apreviously oxidized copper surface at 180C. in an thol, bis(2-oxy-naphthyl)-methane, bis-(2-oxy-3- oxygen atmosphere- The l of the pnonypnaphthylymethane, 1 1 3- z- 5- men is plotted as a function of timeand the time is rebuty| 4 hydmxypheny1)bumne terpene-substituted cordedat which the initial exotherm occurs in the h l d bi h l f examph, 6 i bcurve. This time is the induction time. To be commer- U650], -i 2 4- 2cially acceptable, a formulation should have an induccresol,6-isobornyl-3,4-dimethyl-phenol, 2,6-dition time of at least aboulminutesi b |-3 4-di h h 6 6'- h 1 -bi 2 Quantitatively, the amount ofstabilizer remaining is0b0l-ny| 4 methy|pheno|) 2 4 after the petroleumjelly treatment should be at least dmsobomypphenol) can l be used about25 percent of the original in order for a composi- Particularly suitablethioether compounds are those to be Commercially attractive f aliphaticalcohols containing f to 18 carbon The invention is illustrated in thefollowing examples. atoms such, for example, as di-octyl-sulphide, dir fand Percentages are by weight Unless Otherwise dodecyl-sulphide,di-octadecyl-sulphide and bis(2-0xymdlcatednaphthyl)-sulphide and thecorresponding polythioethers, for example di-dodecyl-disulphide,di-octyl- EXAMPLES l to 6 trisulphide, di-octadecyl-tetrasulphide, andbis( 2- oxynaphthyl)-disulphide esters, preferably those-of ali- Acrystalline propylene--ethylene block copolymer phatic alcoholscontaining four to 18 carbon atoms containing about 22 percent ethyleneand having an insuch, for example, as thio-di-acetic acid dodecyl ester,nSiC vi cosity of 3-7 was compounded with the addithio-di-propionic acidlauryl ester, di-thio di-but ri tives shown in the table below andextruded and pelletacid, octadecyl ester, di-thio-divaleric acid butylester, iZed to form d ng powder he a ious formulationstrithio-didecane-carboxylic acid nonyl ester, tetrathio- 40 were mpr s in molded to orm films 4 X 4 X 0.01 dibutyric acid octyl ester ands-t-butyl-mercapto-acetic inch a 5C fo 5 minutes. Test specimens 1.5 X1.0 acid lauryl ester. Salts of the thiodialkanoic acid esters inch e et f o these and were treated in ml. of such as zinc, calcium or sodiumsalts can also be used. gh-O l petroleum jelly at 85C. for 18 hours.

Petrolatum compositions fall into generally two main he reated Specimenswere tested for D.T.A. inducclassifications those having high oilcontent and 45 n me in Contact with copper under Oxygen at those havinglow oil content. The invention is applical80C. They were also analyzedfor residual thiobisble to either type of petrolatum. Generally, thehigh oil phenol-phosphite by ultraviolet absorption spcctraspetrolatumhas a melting point of about 45 to C., copy. Saybolt viscosity of aboutto 73, and contains about Pertinent data concerning these examples arere- 25 to 35 percent oil or methyl ethyl ketone soluble low 50 corded inthe following table.

'lAB LE- E ample 1 2" 3 4 5 s Contml Ingredients:

iillillireaa;i;a; ,m1s $92 if? if? 592 $93 $93 Zn thlodlpropionate 0.50.5 0.5 Sodium--hydr0xy-3,5-di-t-butyl-benzyl in tiiiiiii iiiiih'(ifiiffifei'iiifi'i'id 'iiIl i i' 13:3 23'? 333 13'3 "45 Percentresid. thiobisphenolphosphite 29 33 25 04 10 27 -10 I Thethlobisphenol-phosphite in this example was re laced b 0.5 art of theeacti d 1 crotonaldehyde and 3 moles of 3-methyl-6-t-butyl phenol & p ron m net of mol of EXAMPLE 7 In this example, an ethylene--propyleneblock copolymer containing about 25 percent ethylene was compounded withthe stabilizing additive shown below.

Ingredients were melt compounded on a two-roll mill (surface temperatureI70-I77C.); 4 X 4 X 0.I in. films were pressed at 215C. for minutes.Portions of these films (about 2 X 2 in.) were placed on glass beads ina Petri dish and were covered with about 20 ml. of a blend consisting of84.8 percent high-oil petroleum jelly, percent low density polyethylenefluff", and 0.2 percent 4,4'-thiobis-(3-methyl-6-t-butyl phenol)antioxidant. The Petri dishes were covered and placed in an oven at 70C.for 250 hours. After removal from the jelly and wiping with a tissue,pieces of the film were then tested for DTA. induction time at 180C.while in contact with a copper dish as described hereinabove.

Ingredients Control Ex. 7 Copolymer I00 I00 Conventional stabilizer 0.50.5 Distearyl thiodipropionate 0.25 0.25 Thiobisphenol phosphite 05Induction time (minutes) 5 56 Reaction product of 3 moles of3-methyl-6-t-butyl phenol and I mole of crotonaldehyde. I

(IJIIQ CH: OH:

What I claim and desire to protect by Letters Patent 1. In anelectrically conductive cable consisting essentially of a plurality ofconducting wires individually coated with an olefin polymer containing astabilizer against the degradative effects of the metal in theconducting wires and having the space between individual conductingwires filled with an amorphous, semi-solid,

Rn R u 3 where R is methyl or t-butyl and n is from 0 to 2.

2. The cable of claim 1 where the thiobisphenol phosphite is 3. Thecable of claim 1 where the polymer contains co-stabilizers in additionto the thiobisphenol phosphite.

4. The cable of claim 3 where the thiobisphenol phosphite is UNITEDSTATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 @755 610Dated August 28 1973 Frank H. McTigue Inventor(s) It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

The present columns 1 through 6 should be cancelled and the attachedcolumns 1 through 6 substituted therefor, as part of the Letters Patent.

Signed and sealed this 25th day of June 1974.

Attest;

EDWARD M.FLETCHER,JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents 1 FORM PO-1050 {10-69) USCOMM-DC 60376-P69 ELECTRICALLYCONDUCTIVE CABLE This invention relates to a new and improved electricalconductor suitable for use in underground installations. Morespecifically it relates to electrical or communications cables comprisedof a plurality of individual polyolefin coated wires.

An electrical or communications cable is comprised of a great number ofpairs of single conductive wires. Each of these singles is coated with adielectric material to insulate them all individually from one another.A large number of these singles are then collected into a bundle whichis the cable. The cable is coated on the outside with a sheath of adielectric material to make an integral structure.

As is to be expected, collecting a plurality of round wires into a cableresults in a large volume of unoccupied space between wires. In thenormal course of things this is simply dead space which becomes filledwith air. In many applications this is satisfactory since air is anexcellent dielectric. However, when the cable is intended to beinstalled underground, this type cable is usually not satisfactory. Thereason for this is that an underground cable is frequently in contactwith water. If a flaw develops in the outer sheath, water can leak intothe dead space in the cable and this can eventually lead to trouble suchas, e.g., shorting of a pair of wires.

In order to keep water out of these cables in .undergroundinstallations, it has become common practice to fill the cable with aninexpensive liquid or low-melting solid dielectric. The most preferredmaterial found for this application is petrolatum or petroleum jellyi.e., a low molecular weight, amorphous, semi-solid hydrocarbon mixturemelting at about 34 to 60C. The filling composition actually used in thecable is composed of 80 to 95 percent petrolatum and 5 to percent low ormedium density polyethylene. The filling compounds become fluid at 100to 125C.

Unfortunately, the use of petroleum jelly is not a satisfactory solutionto the problem, when the dielectric coating on the individual wirestrands or the sheath is a polyolefin such as polyethylene orpolypropylene. These materials contain heat stabilizers and copperinhibitors which are readilyextracted therefrom by the petroleum jellywhich is chemically .very similar to the polymer in its structure. Heatstabilizers and copper inhibitors are needed in polyolefins for use infilled cable to protect the polymer, not only in the buried portion ofthe cable, but especially in the pedestals where the cables are broughtabove ground to make connections. These pedestals get quite warm insummer.

It is the purpose of this invention to provide an improved polyolefinjacketed electrical conductor which is not subject to the same highdegree of stabilizer extraction as is experienced with prior art cables.Concisely stated, the invention is an electrically conductive cableconsisting essentially of a plurality of conducting wires, said wiresbeing individually coated with an olefin hydrocarbon polymer containing,as a stabilizer, a hindered thiobisphenol phosphite and having the spacebetween said wires filled with an amorphous, semisolid, low molecularweight petroleum hydrocarbon melting at about 34 to 60C. Although thethiobisphenol phosphites have been recognized as polyolefin stabilizers,see U.S. Pat. No. 3,354,] 17, their ability to resist extraction bypetrolatum has been hitherto unrecognized.

The jacketed electrical conductors according to this invention can haveas their electrically conductive member either aluminum or copperaccording to known prior art. The make-up of the conductive member apartfrom the coating thereof forms no part of the invention.

As stated, the electrical conductors are coated with a solid polyolefin,i.e., a homopolymer of a single olefin or a copolymer of two or moreolefins. Preferred polyolefins are those based on ethylene andpropylene, for example, polyethylene, polypropylene and copolymerscontaining a preponderance of either ethylene or propylene.

The thiobisphenol phosphites employed in the practice of this invention,which-are readily prepared by the reaction of PCl with a thiobishindered phenol, having the general formula:

where R is methyl or t-butyl and n is from O to 2.

The preferred thiobisphenol for use in preparing the thiobisphenolphosphites of this invention is 4,4- thiobis-(-t-butyl-m-cresol). Otherswhich can be employed include e.g. 4,4-thiobis-(6-t-butyl phenol), 4,4-'-thiobis-(2,6-di-t-butyl-m-cresol), 4,4-thiobis-(2,6-dit-butyl phenol)and 4,4'-thiobis-(2-methyl-6-t-butyl phenol), 2,2'-thiobis(6-t-butylp-cresol), 3,3- thiobis(6-t-butyl p-cresol), 2,2-thiobis(6-t-butylphenol) and 3,3-thiobis(6-t-butyl phenol).

The thiobisphenol phosphite is employed in conceniraii'aii arasanr 6.65%I .Upercefit by vveight based on the weight of the polymer. The otherstabilizers are likewise present in concentrations of about 0.1 to 1.0percent by weight based on the weight of the polymer. The concentrationemployed will depend upon the extractability of the stabilizer and thecon- 'centration which must remain in the polymer when it contacts thepetroleum jelly.

The thiobisphenol phosphites are somewhat unique among polyolefinstabilizers in that they are both phenols and thioethers and,accordingly, provide the two principal functional groups which are foundin' substantially all polyolefin stabilizer systems. In

' practice they are believed to perform both the antioxidant functionexpected from the phenolic compound and the peroxide decomposingfunction expected of the thioether group. Equally, or perhaps moreimportantly, these materials are effective inhibitors of oxidativedegradation catalyzed by copper. The significance of this is obvious inelectrical applications where copper-is a widely used metal.

In view of the versatile character. of the thiobisphenol phosphite, itis possible to prepare useful compositions containing this stabilizeralone. However, in many cases it is desirable to include otherstabilizers, particularly phenolic compounds and thioether compounds.Even though a substantial portion of these may be extracted, theresidual, un-

extracted portion will supplement the effect of the thiobisphenolphosphites and will frequently be substantially less expensive.Moreover, in some formulations, the phenolic antioxidant is, employedprimarily as a heat stabilizer during extrusion and thus no harm thosehaving low oil content. The invention is applicable to either type ofpetrolatum. Generally, the high oil petrolatum has a melting point ofabout 45 to 55C., Saybolt viscosity of about 65 to 73, and containsabout is done if it is later extracted. In such a case, a less 5 25 o 35Percent Oil or m y hy ketone Soluble W expensive t i l b employedmolecular weight hydrocarbons. The low oil petrola- As known phenolicstabilizers which are suitable tum has a melting Point of about toSaybolt there may be mentioned, h lk l h l com viscosity of about 90 to115, and contains about 12 to taining up to 18 carbon atoms in the alkylgroup, for QBEEE lQil- 7 example, p-t-butyl phenol, amyl phe l l l 10The extractability of the various stabilizers 1s deterphenol, p-nonylphenol, p-dodecyl phenol, 2,4- mined by compounding the stabilizer intothe polymer butyl phenol, 2,4-dioctyl phenol, dinonyl phenol, andcomprefsslon f the p y a Q 2 4 1 phenol, z film. A portion of thls film1% X 1 inch is placed m 50 dpoctadecyppwresol nonypresorcinol, dodecyl15 ml. of petroleum elly and treated for 18 hours at 85 droquinone andthe bisphenols, for example, (Jelly to Polymer about to h film 4,4IdiOXy diphenyl dimethyl methane then removed from the petroleum elly andwiped subbis (4 oxy 3 methyl phenyl) pmpane (2 2)g stantlally clean. Aquahtative measure can be obtained 4,4l dioxydiphenyl by means ofa 180DTA induction time. A quantitative bis (4 oxy 3,5 dimethyl phenyl)methane 2O Eiefasure cdanfpe orbtamed bty infrared or U.V. analysis eore an a er e ex rac ion. bis-(40x365'dl't'buty]'phenyn'methana Theinduction time is determined on a Perkin-Elmerbis-(20x36't'butyl's'methyl phenyl) methane Differential ScanningCalorimeter'by heating the film ona previously oxidized copper surfaceat 180C. in an bis (z oxy phenyl) cyclohexane oxygen atmosphere. Theenergy response of the speci- 4 4, thiobis (6 t butyl m cresoli men 18plottedas a funct on of time and the time IS re- Naphthols andbisnaphthols for example dinaph corded at which the nitial exothermoccurs in the tho bis (2 0Xy naphthyl) n;ethane bis:(2-0Xy 3 curve. Thistlme IS the induction time. To be commernonylmaphthyD-methane l l 3-tris-(2-methyl-5-tfig z g i g have an induclOll ime o a eas a ou mmu es.3221:3223253523515522mmfizi zzzzfsrlrini of cresol 6 isobomyl 4 Xylenol2 6 di isobomyl p after the petroleum elly treatment should be at leastcresol, 6 iSobmyl 3';4 dimeth3{l p}leno|, 2,64% about 25 percent of theorlgmal n order for a compostisobornyl-3,4-dimethyl-phenol,6,6'-methylene-bis-(2- rF fi f g z n l isobornyl-4-methylphenol),6,6'-methylene-bis- (2,4- emven lonlsl ustrat'e mt F: O owmg exampdidsobomybphenol), can also be used- Parts and percentages are by weightunless otherwise Particularly suitable thioether compounds are thoseindlcat'eg: of aliphatic alcohols containing four to 18 carbon vEXAMPLES l to 6 atoms such, for example, as di-octyl-sulphide, di- Acrystalline propylene-ethylene block copolymer dodecyl-sulphide,di-octadecyl-sulphide and bis( 2-0xy- 40 containing about 22 percentethylene and having an innaphthyl)-sulphide and the corre ondipolythioetrinsic viscosity of 3.7 was compounded with the addithers, forexample di-dodecyl-disulphide, di-octyltives shown in the table belowand extruded and pellettrisulphide, di-octadecyl-tetrasulphide, andbis(2 ized to form molding powder. The various formulationsoxynaphthyl)-disulphide esters, preferably those of ali- WereCompression molded to form films. 4 X 4 X 0.01 phatic alcoholscontaining four to 18 carbon atoms 5 inch at 215C. for 5 minutes. Testspecimens 1.5 X 1.0 such, for example, as thio-di-acetic acid dodecylester, inch were cut from these and were treated in ml. ofthio-di-propionic acid lauryl ester, di-thio-di-butyric high-oilpetroleum jelly at C. for 18 hours. acid, octadecyl ester,di-thio-divaleric acid butyl ester, The treated specimens were testedfor D.T.A. inductrithio-didecane-carboxylic acid nonyl ester,tetrathiotion time in contact with copper under oxygen at dibutyric acidoctyl ester and s-t-butyl-mercapto-acetic 50 180C. They were alsoanalyzed for residual thiobis- :33. Z: 315 lii'cfii oi siiiiilliil fif138111123 Z" Mamet absmpm spew Petrolatum compositions fall intogenerzfily two main Pertinent data concerning these examples arereclassifications those having high oil content and cord d i th f ll ibl Ha TABLE Example 1 2 a 4 5 5 Control Ingredients:

Polymer 100 100 100 100 100 100 Thlobisphenol phosphite b O. 5 O. 6 0. 10.3 0.6 0.3 Zn thiodiproplonate 0.5 0.5 0.5Sodium-4-hydroxy-3,5-di-t-butyl-benzyl sulfonate) 0.5 0.5 0.5 0.5 0.5Induction time (minutes) (DTA at 180 0).. 25.5 28.2 14.8 22.5 30.0 18.05 Percent resld. thiobisphenolphosphite 2U 33 25 34 40 27 -10 EXAMPLE 7In this example, an ethylene--propylene block copolymer containing aboutpercent ethylene was compounded with the stabilizing additive shownbelow.

Ingredients were melt compounded on a two-roll mill (surface temperaturel70l77C.); 4 X 4 X 0.10 in. films were pressed at 215C. for 5 minutes.Portions of these films (about 2 X 2 in.) were placed on glass beadslngredients Control Ex. 7 Copolymer 100 100 Conventional stabilizefl 0.50.5 Distearyl thiodipropionate 0.25 0.25 Thiobisphenol phosphite" 0.5Induction time (minutes) 5 56 *Reaction product of 3 moles of3-methyl-6-t-butyl phenol and 1 mole of crotonaldehyde.

311. pHTom CHaCOHa c-om 9" I I P CH3 CH3 3 What I claim and desire toprotect by Letters Patent 1. In an electrically conductive cableconsisting essentially of a plurality of conducting wires individuallycoated with an olefin polymer containing a stabilizer against thedegradative effects of the metal in the conducting wires and having thespace between individual conducting wires filled with an amorphous,semi-solid,

low molecular weight petroleum hydrocarbon melting at about 34 to 60C.,the improvement which comprises said stabilizer being about 0.05 to 1percent by weight, based on polymer weight, of a hindered thiobisphenolphosphite having the general formula where R is methyl or t-butyl and nis from O to 2.

2. The cable of claim 1 where the thiobisphenol phosphite is ea. 7' CH3CHa-C-CHa CHa-(iJ-CH:

P H O- S O- 3. The cable of claim 1 where the polymer containsco-stabilizers in addition to the thiobisphenol phosphite.

4. The cable of claim 3 where the thiobisphenol phosphite is

2. The cable of claim 1 where the thiobisphenol phosphite is
 3. Thecable of claim 1 where the polymer contains co-stabilizers in additionto the thiobisphenol phosphite.
 4. The cable of claim 3 where thethiobisphenol phosphite is